Dam and drive across Nant Meigan on Baron Hill estate is a Grade II listed building in the Isle of Anglesey local planning authority area, Wales. First listed on 13 July 2005. Dam.

Dam and drive across Nant Meigan on Baron Hill estate

WRENN ID
stony-crypt-mint
Grade
II
Local Planning Authority
Isle of Anglesey
Constituency
Ynys Môn MP: Llinos Medi (PC)
Country
Wales
Date first listed
13 July 2005
Type
Dam
Address
Dam and drive across Nant Meigan on Baron Hill estate, Nant Y Felin, Beaumaris
OS grid reference
SH 596 759
Coordinates
53.26204, -4.10488
Source
Cadw listing

Also on this page: flood risk · radon risk · weather exposure · detailed attributes ↓

Description

The dam and drive across Nant Meigan on the Baron Hill estate is a monumental masonry structure designed to close the head of Nant y Felin, impounding the stream for both industrial and picturesque purposes. It features coursed and random masonry that stands approximately 14 meters high, with a heavily battered profile supported by four large raked buttresses. At mid-height, there is a segmentally-arched and brick-vaulted tunnel that includes a projecting stone sill for the main water outlet, along with a ramped spillway situated between the buttresses. Lower down on the right, there is a second outfall beneath a long, now split, lintel that used to feed a stone-lined leat leading downhill to a former slate dressing mill, which was rebuilt in 1675. A driveway runs along the top of the dam, with a pond on the upper side, and continues north to a bridge over the B5109, leading to the ruins of Baron Hill beyond.

Local climate

Dam and drive across Nant Meigan on Baron Hill estate sits in one of the wettest parts of the UK, with an average of 1,210 mm of rain a year. This makes it wetter than 92% of listed buildings in the UK. Its exposure to wind-driven rain is greater than that of 90% of listed buildings.

It experiences an average of 37 freeze-thaw cycles a year, more than 67% of listed buildings. Of these, 19 follow at least 1 mm of rain in the preceding 48 hours. Average temperatures at this location have risen by 0.3°C per decade since 1991.

Averages for 1991–2020; temperature trend 1991–2025. Figures describe the wider area (a grid cell of roughly 10 km), not the individual site. Contains modified Copernicus Climate Change Service information 2026.

More on this building

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Nearby listed buildings

  1. Ice house at Baron Hill Grade II 259 m
  2. Ysgol Gynradd Beaumaris Primary School including attached range to right Grade II 330 m
  3. White Cottage Grade II 352 m
  4. Bridge over B5109 on drive to Baron Hill Grade II 364 m
  5. Bridge over Mill Lane on former drive to Baron Hill Grade II 365 m
  6. Outbuilding behind 4 Tros yr Afon Grade II 391 m
  7. 4 Tros yr Afon Grade II 405 m
  8. 3 Tros yr Afon Grade II 412 m
  9. 1 Tros yr Afon Grade II 419 m
  10. 2 Tros yr Afon Grade II 420 m